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A Computation
A.1 Computation of Molar Weight & Specific Volume of Gas
A.1.1 Moler weight of Fuel gas composition
Molecular
weight (M)
Mole %
(F)
Moler
weight
(gm) (M
X F)
Nitrogen (N2) 28 1.4 40.2
Methane (CH4) 16 91.7 1467.0
Ethane (C2H6) 30 4.5 135.0
Propane (C3H8) 44 0.8 33.0
Butane (C4H10) 58 0.3 15.5
Pentane (C5H12) 72 0.1 5.7
Total weight of 98.7 mole = 1696.4 gm
Molar weight of gas = 17.18361 gm
(For molecular weight of individual constituent of gas, Refer
Attachment)
Specific gravity of the gas = Molar weight of gas / 28.95
= 0.5936
A.1.2 Specific volume of Fuel gasSpecific volume of gas =
Molar weight of gas
where 22.4 litre is the molar volume of any gas a
= 22.4 / 17.184
= 1.3036 m3/kg at NTP
Pressure P1 = 0 bar g
Temperature T1 = 0
o
CSpecific volume V1 = 1.3036 Nm
3/kg
Pressure P2 = 3.5 bar g
Temperature T2 = 60oC
Specific volume V2 = 0.35697879 m3/kg
Pressure P1 = 0 bar g
Temperature T1 = 0oC
NTP
Per design basis 2.3, the composition of natural gas along with
the computation of mola
Composition
22.4
Aux. Boiler
NTP
condition
Acutal
Condition
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Specific volume V1 = 1.3036 Nm3/kg
Pressure P2 = 45.1 bar g
Temperature T2 = 60oC
Specific volume V2 = 0.034938646 m3/kg
As per Ideal gas equation, for a fixed quantity of gas
V2 = P1 X V1 X T2 T1 X P2
Pressure P2 = 0 bar g
Temperature T2 = 15oC
Specific volume V2 = 1.375192346 m3/kg
Calorific Valve of Fuel Gas CV = 800 Btu/scf
17622.79341 Btu/lb
Auxiliary Boiler Sizing
Fuel Gas Parameters :
Fuel Gas Terminal Pressure 3.5 Bar,g
Fuel Gas Terminal Temperature 60 Deg.C
Fuel Gas Specific Volume (Operating Condition) 0.3570 m3/kg
Fuel Gas Specific Volume (Standard Condition) 1.3752 m3/kg
Fuel Gas Enthalpy 800 Btu/scf
17622.8 Btu/lbs
Aux Boiler Heat Load 15368305.5 Btu/hr From Anti I
Fuel Gas flow rate required 1014.0 lb/hr
550.0 kg/hr
196.3 m3/hr
Considering 10% margin on flow 216 m3/hr
Gas Turbine Sizing
Fuel Gas Parameters :
Fuel Gas Terminal Pressure 45.1 Bar,g
Fuel Gas Terminal Temperature 60 Deg.C
Fuel Gas Specific Volume (Operating Condition) 0.0349 m3/kg
Fuel Gas Specific Volume (Standard Condition) 1.3036 m3/kg
Fuel Gas Enthalpy 800 Btu/scf
16704.9 Btu/lbs
Gas
Turbine
Acutal
Condition
STP
Condition
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Aux Boiler Heat Load 430000000.0 Btu/hr From Gas T
Fuel Gas flow rate required 29931.3 lb/hr
14950.0 kg/hr
522.3 m3/hr
Considering 10% margin on flow 575 m3/hr
453.674
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t NTP.
weight is as under.
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cing Calculation
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urbine Data
